Casting



Nov. 7, 1944. T. s. JUNGERSEN Y 2,362,136

CASTING Original Filed Jan. 11, 1940 s Sheets-Sheet 1 Nov. 7, 1944. 1-,e. JUNG-ERSEN 2,362,136 I CASTING Original Filed Jan. 11, 1940 3Sheets-Sheet 2 gfmywm,

Nov. 7, 1944. T, G. JUNGERSEN 2,362,136

CASTING Original Filed Jan. 11, 1940 Q3 Sheets-Sheet 5 v 7%0ya9 Wi wamPatented Nov. 7, 1944 ThogerG. Jungersen, Summit, N. J.

Original application January 11, 1940, Serial No.

Divided and this application December 18, 1943, Serial N0. 514,838

(01. 22-200) The present invention relates to the art of 8 Claims.

making jewelry and other small metal articles of intricate design andfine detail, and among other objects, aims to provide an improvedprocess or method of casting such articles.

A further object of the invention is to enable the. formation ofintricate castings which will so closely resemble the original andfinished product that the slow and tedious work of patterning and detailcutting required in connection with present casting methods iseliminated.

It is still a further object of the instant invention to provide aprocess of casting low temperature fusing metal and other materialsdirectly into 'a plural part moldwhich may be of rubber to form objectsof intricate design suitable for commercial or other use includingrelatively inexpensive jewelry.

Other objects and features of the invention will be evident, includingthe various steps of the improved process and attendant advantages overanything heretofore known, as set out in the foregoing description of amethod and apparatus suitable for reproducing inexpensive lowtemperature fusing metals and other materials, articles, and jewelryespecially of intricate design, such as articles containing hollows,undercut portions, and perforations, and of certain apparatus andmaterial preferred for use in practicing the invention.

This application is a division of my copending application Serial No;313,458, filed January 11,

Fig. 1 is an elevational view 'of a centrifugal casting machine;

Fig. 2 is an elevational view of the casting made in the mold partsillustrated in Figure 5.

Fig. 3 is a view in perspective of a model resting on a partiallyprepared rubber mold part; Fig. 4 is a longitudinal sectional view ofthe model resting on the partially prepared rubber mold part, andanother mold part resting on said model, the assembly being arranged ina press;

Fig. 5 is a view similar to Figure 4 with the press in closed position;

Fig. 6 is a fragmentary sectional view of a mold part burned by a hotpointed instrument in order to facilitate removal of the setting portionof the ring mold; and

' Fig. 7 is a view in perspective of the completed mold taken from thepress shownin Figs. 4 and 5.

A method of making a mold suitable for the casting therein of intricatedesigns, such as jewelry, including ladies rings, comprises theutilization of plastic mold parts, such as rubber mold parts, as will bedescribed in connection with the drawings. The pattern 200 including asprue former -20I is rested upon an unvulcanized rubber block 202, seeFig. 3. which may have a cutout portion or aligning deformation 203aabout the margin of its upper face- 204 and inspaced relation tothemodel 200. The said upper face is then coated with a suitabl partingmaterial 205, such as an oil or talcum powder, or other powder that willnot injure the rubber. A second block of unvulcanized rubber 203, seeFig.4, is then arranged over the model to sandwich the model between theblocks 202 and 203. The sandwiched assembly is then placed in a pressand vulcanizing machine 206. After heat and pressure are applied to theblocks 202 and 203, see Fig. 5, they will take the form illustrated andeffect a plural part mold such as illustrated in Fig. 7 after a gate 201is cut into the now vulcanized block 203 in-communicating relation withthe sprue former by the sprue former 20l. Due to the application of heatand pressure, the interlocking projection 203a will be formed tocorrespond to the aligning depression 203. The finished mold shown inFig. 7 may then be utilized to cast objects of intricate design.

It may be desirable to cut the two rubber mold sections at variousselected points, so that they may be easily removed from the castingformed therein. If the casting is quite plain in design, cutting may notbe necessary as the flexibility of the mold section may be sufficient topermit their manual separation from the casting. If the casting isintricate such cutting becomes necessary. The location and direction ofthe cuts, and their number, will be indicated by the particular design,the object being to insure separation of the rubber mold from thecasting, which may be of low temperature fusing metal, without anydistortion or other injury whatever to the latter. and withoutdetrimentally affecting the accuracy or details of the mold. As anexample, there is shown in Fig. 6, a rubber mold portion 22, with adeeply undercut or hollowed model P, the actual volume of which may bereduced by the insertion of a heated pointed instrument I to form acavity 8 therewithin. Moreover, a plurality of slits 9 are cut into theopposite sides to extend part way across the mold body, so that therespective portions will be free to flex easily in being withdrawnthrough the opening I0 of the model P.

The two registering rubber mold sections thus formed about the model aredepicted in Fig.7 of the drawings. According to the preferred embodimentof the invention, these two sections are produce a casting of intricatedesign.

Prior to the casting of the low temperature I fusing metal or othermaterial the registering surface of the two mold sections may be coveredwith a fluid or other suitable substance or lubricant for facilitatingtheir separation. Such a substance is preferably an oil, which will notinjure the mold, such as for example, castor oil. If the casting is tobeformcd from a readily fusible metal, such as "Woods metal, theseparating material may assume the form of a dry powder, The moldsections are brought together and sufiiciently tightly clamped toprevent their distortion, yet flrmly enough to assure a faithfulreproduction of the original model and the flexible mold is now readyfor the casting therein of the low temperature fusing metal or othermaterial.

The flexible mold is now preferably put in a centrifugal castingmachine. These machines are already available machines of commerce, andan illustration of such a typical machine M is found in Fig. 1,diagrammatically showing a mold in position therein. Instead ofemploying such a machine, the article to be formed may be cast bycentrifugal force exerted manually, as by whir1 ing the mold on the endof a string or cord. It is to be understood that other force suflicientto effect the entrance of the material within the intricacies of themold may be utilized without departing from the spirit of the invention.

It is preferred to employ centrifugal force when casting readily fusiblemetal or other material in a rubber mold, for the reason thatcentrifugal force acts in a peculiar way to cause the molten material tocompletely fill the mold space and yet permit escape of all the airthrough the center of the mold cavity while the molten material is stillliquid with the result that the casting is a perfect reproduction of thecavity in the mold. Thus any air which may be trapped in a recess of themold will be crowded back into the fluid body under the pressure appliedthereto and the fluid material will progress into the recess of the moldas it crowds the air therefrom and will progressively congeal againstthe wall of the recess until the extreme limits are reached so that thefinest of cavities will be completely filled. Either centrifugal forceor an applied pressure is very essential in the production of perfectcastings in read ily fusible material, especially where the castings areof small dimensions and/or of intricate design.

The resultant casting C, whether of readily fusible metal or othermaterial requires nothing but extremely simple finishing operations tobe ready for the market. The only part of the casting requiring anyrough finishing work at all is the part H, see Fig. 2, where the spruejoins the casting, which may be smoothed by filing, grinding, cutting orotherwise. The final bufling and polishing operation may thus beperformed directly on the article as removed from the mold. Thus theprocess effects very large savings especially in the manufacture ofjewelry of intricate I design.

With known processes of casting small articles of intricate design suchas the cuttlefish process, for example, it may take an expert workmanseveral hours to finish the article to a commercial standard, while withthe present process only a few minutes are required to finish thearticle to the same standard.

It is to be understood that it is within the scope of the invention toutilize the casting C as a model to make further castings, if desired.

It is contemplated that synthetic rubber such as polymerized chloro 2butadiene 1,3 be utilized in place of natural rubber as the moldmaterial.

It will be obvious to those skilled in the art that various changes maybe made in this device without departing from the spirit of theinvention and therefore the invention is not limited to what is shown inthe drawings and described in the specification but only as indicated inthe appended claims.

I claim:

1. In a process for casting pieces of Jewelry or other articles ofintricate design from the low temperature fusing metals, the stepscomprising making a plural part mold by arranging one or more models ofthe articles to be cast between a plurality of slabs of flexible moldforming material, making registry formations between contacting surfacesof said slabs, applying a separating medium to the contacting surfacesof said slabs, setting the slabs within a confined space under theinfluence of heat and pressure to make a relatively rigid butpermanently flexible mold capable of withstanding successive castingtherewithin of articles of the low temperature fusing metals bycentrifugal force, successively casting articles of low temperaturefusing metals within saidmold by centrifugal force.

2. The process recited in claim 1, said mold forming material whichunder the influence of heat and pressure forms a permanently flexiblemold being rubber.

3. The process recited in claim 1, the articles .corresponding to saidmold being cast in that metal group consisting of tin and tin alloys.

4. The process recited in claim 1, said articles corresponding to saidmold being cast in that metal group consisting of lead and lead alloys.

5. A process of casting articles intricate to the extent of having oneor more small projections or depressions comprising: making a pluralpart mold by arranging one or more models of the articles to be castbetween a plurality of slabs of flexible mold forming material, makingregistering formations between contacting surfaces of said slabs,applying a separating medium to contacting surfaces of said slabs,molding the slabs about the model or models under the influence of heatand pressure to form a relatively rigid though permanently flexible moldcapable of withstanding successively casting therewithin articles by anapplied force suflicient to fill the mold cavity in all its intricatedetails, successively casting articles within said mold within anapplied force sufficient to fill the mold cavity in all of its intricatedetail.

6. The process recited in claim 5, said mold forming material whichunder the influence of heat and pressure forms a permanently flexiblemold being rubber.

'l. The process recited in claim 5, the articles corresponding to saidmold being cast in. that metal group consisting of tin and tin alloys.

8. The process recited in claim 5, said articles corresponding to saidmold being cast in that metal group consisting of lead and lead alloys.

THOGER G. JUNGERSEN.

